The present invention relates to miniature drug delivery devices and, in particular, it concerns drug delivery devices with particularly low flow rates, and inserter systems for introducing such devices into the body.
It is known to provide an implantable device which delivers a drug slowly over a period of time. This approach avoids problems of patient compliance, and provides particular advantages where delivery of a drug to a specific target location allows use of much lower overall dosage than would be required for systemic delivery, possibly avoiding undesirable side effects.
In some cases, slow drug delivery is achieved by providing a drug is dispersed in a matrix of resorbable material and is gradually released as the matrix breaks down in the body. Examples of this approach may be found in U.S. Pat. Nos. 4,351,337 and 4,450,150 to Sidman. This approach typically does not achieve highly uniform drug release rates, and is not suitable for drugs which must be delivered in a liquid form or which have high diffusion rates through the matrix materials.
Examples of implantable devices for delivery of liquid drugs include, but are not limited to, U.S. Pat. Nos. 5,163,920, 4,428,397, 4,820,273, 5,061,242, 5,993,414, 6,183,461 and 5,836,935.
Certain potential applications of such devices impose particularly demanding conditions. For example, ocular applications pose a challenge as to how to anchor an implanted device so that it does not drift within the internal cavity of the eye. Furthermore, the procedure for introducing and anchoring a highly miniature drug delivery device is difficult to perform reliably and safely.
There is therefore a need for inserter systems for introducing and anchoring miniature drug delivery devices into a body structure such as the eye.